org.apache.calcite.schema

Interface TableFactory<T extends Table>

Type Parameters:

T - Sub-type of table created by this factory

public interface TableFactory<T extends Table>

Factory for Table objects.

A table factory allows you to include custom tables in a model file. For example, here is a model that contains a custom table that generates a range of integers.

{
   version: '1.0',
   defaultSchema: 'MATH',
   schemas: [
     {
       name: 'MATH',
       tables: [
         {
           name: 'INTEGERS',
           type: 'custom',
           factory: 'com.acme.IntegerTable',
           operand: {
             start: 3,
             end: 7,
             column: 'N'
           }
         }
       ]
     }
   ]
 }
 
 

Given that schema, the query

SELECT * FROM math.integers

returns

+---+
 | N |
 +---+
 | 3 |
 | 4 |
 | 5 |
 | 6 |
 +---+
 

A class that implements TableFactory specified in a schema must have a public default constructor.

Method Summary

Methods

Modifier and Type	Method and Description
T	create(SchemaPlus schema, String name, Map<String,Object> operand, RelDataType rowType) Creates a Table.

Method Detail

create

T create(SchemaPlus schema,
       String name,
       Map<String,Object> operand,
       RelDataType rowType)

Creates a Table.

Parameters:

schema - Schema this table belongs to

name - Name of this table

operand - The "operand" JSON property

rowType - Row type. Specified if the "columns" JSON property.